The present invention relates to active mounts which are introduced between a machine and foundation or other supporting structure. In particular, the present invention relates to active mounts for sensing and attenuating vibrational forces transmitted by dynamic loads from a machine, such as a motor, through a resilient mount such as by elastomers or springs, further either using a least mean square analysis which employs a reference sinusoid synchronous with the rotation of the motor and signal from a load cell or using a high gain broadband control circuit that amplifies the load cell signal over a wide frequency range which includes the motor running speed and running speed harmonic frequency component ranges, thereby generating a control signal to an electromagnet.
Various types of equipment utilizing soft mounts are known which perform two functions:
1. Isolate the forces generated by the equipment from the foundation and surroundings; and
2. Isolate external forces and disturbances from the equipment.
This is most usually accomplished by the use of soft mounts. The low mount stiffness ensures that the equipment/ base/mount combination has a low natural frequency. Disturbances at frequencies above the natural frequency are attenuated to accomplish both of the above functions.
Usually, rubber is the most generally used material. Cross-sectional areas are dictated by rubber bearing stress limits. Area and the modulus of rubber result in a practical allowable size which limits how low the mount stiffness can be. In short, while dynamic force transmission levels can be reduced, some force will still be transmitted. Further force reduction is not possible with a purely passive system.
Accordingly, it would be advantageous to develop a mount which avoids the drawbacks associated with the aforementioned prior art proposals.